From b2c252fbc218ec95c449ae7f2263d98a6f87c900 Mon Sep 17 00:00:00 2001
From: Laria Carolin Chabowski <laria@laria.me>
Date: Sun, 2 Jan 2022 17:21:16 +0100
Subject: [PATCH] main.c: Add repl mode switching

You can now choose, if you want to play around with the tokenizer, parser
or evaluator in the repl.
---
 src/main.c | 164 ++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 136 insertions(+), 28 deletions(-)

diff --git a/src/main.c b/src/main.c
index 1efa056..9855d2a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -5,6 +5,12 @@
 
 #include "apfl.h"
 
+enum repl_mode {
+    REPL_TOKENIZER,
+    REPL_PARSER,
+    REPL_EVAL,
+};
+
 static bool
 repl_source_reader(void *context, char *buf, size_t *len, bool need)
 {
@@ -28,55 +34,157 @@ repl_source_reader(void *context, char *buf, size_t *len, bool need)
     return true;
 }
 
-int
-main(int argc, const char **argv)
+static int
+repl_tokenizer(apfl_tokenizer_ptr tokenizer)
 {
-    (void)argc;
-    (void)argv;
-
-    int rv = 0;
-
-    apfl_tokenizer_ptr tokenizer = NULL;
-    apfl_parser_ptr parser = NULL;
-
-    if ((tokenizer = apfl_tokenizer_new(repl_source_reader, NULL)) == NULL) {
-        fprintf(stderr, "Failed initializing tokenizer\n");
-        goto exit;
-    }
-
-    if ((parser = apfl_parser_new(apfl_tokenizer_as_token_source(tokenizer))) == NULL) {
-        fprintf(stderr, "Failed initializing parser\n");
-        goto exit;
-    }
-
     while (true) {
         struct apfl_error err;
-        struct apfl_expr expr;
+        struct apfl_token token;
 
-        switch (apfl_parser_next(parser)) {
+        switch (apfl_tokenizer_next(tokenizer, false)) {
         case APFL_PARSE_OK:
-            expr = apfl_parser_get_expr(parser);
-            apfl_expr_print(expr, stdout);
-            apfl_expr_deinit(&expr);
+            token = apfl_tokenizer_get_token(tokenizer);
+            apfl_token_print(token, stdout);
+            apfl_token_deinit(&token);
 
             break;
         case APFL_PARSE_EOF:
-            goto exit;
+            return 0;
+        case APFL_PARSE_ERROR:
+            err = apfl_tokenizer_get_error(tokenizer);
+            apfl_error_print(err, stderr);
+
+            if (APFL_ERROR_IS_FATAL(err)) {
+                return 1;
+            }
+            break;
+        }
+    }
+}
+
+static bool
+repl_parser_generic(apfl_parser_ptr parser, struct apfl_expr *expr, int *rv)
+{
+    while (true) {
+        struct apfl_error err;
+
+        switch (apfl_parser_next(parser)) {
+        case APFL_PARSE_OK:
+            *expr = apfl_parser_get_expr(parser);
+            return true;
+        case APFL_PARSE_EOF:
+            *rv = 0;
+            return false;
         case APFL_PARSE_ERROR:
             err = apfl_parser_get_error(parser);
             apfl_error_print(err, stderr);
 
             if (APFL_ERROR_IS_FATAL(err)) {
-                rv = 1;
-                goto exit;
+                *rv = 1;
+                return false;
             }
             break;
         }
     }
+}
+
+static int
+repl_parser(apfl_parser_ptr parser)
+{
+    struct apfl_expr expr;
+    int rv;
+    while (repl_parser_generic(parser, &expr, &rv)) {
+        apfl_expr_print(expr, stdout);
+        apfl_expr_deinit(&expr);
+    }
+    return rv;
+}
+
+static int
+repl_eval(apfl_parser_ptr parser, apfl_ctx ctx)
+{
+    struct apfl_expr expr;
+    int rv;
+    while (repl_parser_generic(parser, &expr, &rv)) {
+        struct apfl_result result = apfl_eval(ctx, expr);
+        switch (result.type) {
+        case APFL_RESULT_OK:
+            apfl_value_print(result.value, stdout);
+            apfl_value_deinit(&result.value);
+            break;
+        case APFL_RESULT_ERR:
+            fprintf(stderr, "Error occurred during evaluation.\n");
+            break;
+        case APFL_RESULT_ERR_FATAL:
+            fprintf(stderr, "Fatal error occurred during evaluation.\n");
+            return 1;
+        }
+    }
+    return rv;
+}
+
+int
+main(int argc, const char **argv)
+{
+    int rv = 0;
+
+    enum repl_mode mode = REPL_PARSER;
+
+    if (argc > 1) {
+        if (apfl_string_eq(argv[1], "tokenizer")) {
+            mode = REPL_TOKENIZER;
+        } else if (apfl_string_eq(argv[1], "parser")) {
+            mode = REPL_PARSER;
+        } else if (apfl_string_eq(argv[1], "eval")) {
+            mode = REPL_EVAL;
+        } else {
+            fprintf(stderr, "Unknown mode: %s\n", argv[1]);
+            return 1;
+        }
+    }
+
+    apfl_tokenizer_ptr tokenizer = NULL;
+    apfl_parser_ptr parser = NULL;
+    apfl_ctx ctx = NULL;
+
+    if ((tokenizer = apfl_tokenizer_new(repl_source_reader, NULL)) == NULL) {
+        fprintf(stderr, "Failed initializing tokenizer\n");
+        rv = 1;
+        goto exit;
+    }
+
+    if (mode >= REPL_PARSER) {
+        if ((parser = apfl_parser_new(apfl_tokenizer_as_token_source(tokenizer))) == NULL) {
+            fprintf(stderr, "Failed initializing parser\n");
+            rv = 1;
+            goto exit;
+        }
+    }
+
+    if (mode >= REPL_EVAL) {
+        if ((ctx = apfl_ctx_new()) == NULL) {
+            fprintf(stderr, "Failed initializing context\n");
+            rv = 1;
+            goto exit;
+        }
+    }
+
+    switch (mode) {
+    case REPL_TOKENIZER:
+        rv = repl_tokenizer(tokenizer);
+        break;
+    case REPL_PARSER:
+        rv = repl_parser(parser);
+        break;
+    case REPL_EVAL:
+        rv = repl_eval(parser, ctx);
+        break;
+    }
 
 exit:
     apfl_tokenizer_destroy(tokenizer);
     apfl_parser_destroy(parser);
+    apfl_ctx_destroy(ctx);
 
     return rv;
 }